Abstract: The aims of this article are to review recent studies on ammonium assimilation via the GS/GOGAT cycle in higher plants More than 95% of the ammonium, derived from various metabolisms and uptake from soil, are thought to be assimilated via GS/GOGAT cycle GS and GOGAT can be found in leave, nodules and roots The role of GS/GOGAT cycle is to assimilate the ammonium from photorespiration and nitrate reduction in leave, the ammonium from nitrogen fixation in nodule and the ammonium from absorption by roots from soil and nitrate reduction in roots The regulatory mechanisms of the GS/GOGAT cycle are not clear But the advances of gene engineering technology, immunocyto chemistry and modern physiological technology can help us to better understand the regulatory mechanisms of the GS/GOGAT cycle With modern biotechnology held, the plant nutrition studies can expand more To better understand the regulatory mechanisms of the GS/GOGAT cycle is essential to adequately apply nitrogen fertilizer and improve plant nitrogen use efficiency